Food irradiation using -rays is one of powerful tools to reduce insect infestation in crops and spices. We examined the effects of -irradiation on larvae and adults of Tribolium castaneum. Eclosion for larvae was completely inhibited by irradiation at 500 Gy. A survival rate for adults was markedly reduced by irradiation at more than 500 Gy. The neutral comet assay presented that irradiation irreversibly increased DNA damage at 500 and 1000 Gy and transiently increased DNA damage at 100 Gy, suggesting possible DNA repair in larvae and adults stages. These results indicate that -irradiation at 500 Gy is available to eradicate the beetle at larval and adults stages.